In recent years, more and more designers or engineers pay more attention to the initial cost and possible ecnomic loss, namely total life-cycle cost. In this paper, the composition of life-cycle cost for the isolated structure is analyzed in detail. The specific evaluation model of initial cost used as detailed analysis and the general evaluation model used as a preliminary analysis are established, and the calculation method of the operation and the maintenance cost for the isolated structure is introduced.Then the composition of failure loss cost and its calculation method are given. At last, the total evaluation model of life-cost is presented.By analyzing the numeral example, it is proved that the initial cost of the isolated structure may be higher than that of the traditional seismic structure, but in the whole life period, the cost of the isolated structure is lower than that of the general seismic structure, namely the isolated structure still has the advantage with investment-benefit criterion.